Doped Lanthanum Dioxide Carbonate Catalyst for Higher C2 Yield
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for synthesizing lanthanum dioxide carbonate result in low yields of C2 hydrocarbons during methane oxidative coupling, and there is a lack of reports on element doping during the preparation process.
Innovation Solution
A lanthanum dioxide carbonate catalyst is prepared by adding a doping element to lanthanum hydroxide, followed by calcination in a carbon-containing atmosphere, resulting in a catalyst with a high hexagonal crystalline phase content and specific molar ratios, enhancing methane oxidative coupling efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional preparation methods (precipitation, thermal decomposition, hydrothermal) are used to synthesize lanthanum dioxide carbonate, then the material can be obtained with different morphologies or structures, but the C2 hydrocarbons yield during methane oxidative coupling is low
Solution Approach 1:
The patent changes the chemical composition parameter by introducing doping elements (Mg, Ca, Sr, Ba, Fe, or Zn) into the lanthanum dioxide carbonate structure. This compositional modification transforms the catalyst's performance, achieving high C2 hydrocarbons yield (15.00-18.03%) while maintaining a relatively simple two-step preparation process involving doping during precipitation and controlled drying.
Solution Approach 2:
The patent creates a composite catalyst system by incorporating doping elements into the lanthanum dioxide carbonate matrix. The composite structure combines La2O2CO3 with small amounts of secondary elements, forming a multi-component material that exhibits enhanced catalytic activity for methane oxidative coupling, resolving the contradiction between simplicity and effectiveness.
2Ease of manufacture
If element doping is performed by impregnating pre-synthesized lanthanum dioxide carbonate with doping element solutions, then doping can be achieved, but the doping is not completed during the preparation process and requires additional steps
Solution Approach 1:
The patent merges the doping step with the precipitation step by adding doping element salts to the lanthanum salt solution before precipitation occurs. This combination eliminates the need for separate impregnation steps, allowing doping to be completed during the preparation process itself. The dual-drying procedure ensures thorough incorporation of doping elements into the precipitated structure.
Solution Approach 2:
The patent performs preliminary doping action by incorporating doping elements into the precursor solution before precipitation. This preliminary incorporation ensures that doping elements are present during crystal formation, allowing the doping process to be completed during preparation rather than requiring post-synthesis impregnation steps.
3Stability of the object's composition
If low temperature calcination is used to preserve the hexagonal crystalline structure, then the structure can be maintained, but the doping element incorporation may be insufficient
Solution Approach 1:
The patent optimizes the drying parameters (temperature and time) to achieve complete doping element incorporation without requiring high-temperature calcination. The two-stage drying process (70-90°C for 10-20 hours followed by higher temperature for shorter time) transforms the precursor into the final hexagonal phase with proper doping, maintaining structural stability while ensuring precise doping incorporation.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The catalyst achieves a higher yield of C2 hydrocarbons during methane oxidative coupling, with a catalyst structure that ensures high purity and activity.
Implementation Method 1
wherein the contacting method is selected from surface precipitation, atomic layer deposition and single atomic layer plating
Implementation Method 2
wherein the contacting method is selected from surface precipitation, atomic layer deposition and single atomic layer plating
Implementation Method 3
wherein the contacting method is selected from surface precipitation, atomic layer deposition and single atomic layer plating
Implementation Method 4
calcining the dried product of step (2) in a carbon-containing (e.g. CO and/or CO2) atmosphere to obtain a lanthanum dioxide carbonate catalyst
Data Source
AI summary
A lanthanum dioxide carbonate catalyst, a preparation method and a use thereof are provided. The lanthanum dioxide carbonate catalyst comprises hexagonal crystalline lanthanum dioxide carbonate and hexagonal crystalline lanthanum dioxide carbonate containing a doping element R. The method includes the steps of (1) adding an alkali solution to a solution of lanthanum source, and then performing a solid-liquid separation and a drying to obtain lanthanum hydroxide; (2) contacting a solution of a compound containing the doping element R with lanthanum hydroxide, and then performing a drying; (3) calcining the dried product of step (2) under a carbon-containing atmosphere to obtain a lanthanum dioxide carbonate catalyst.